Summary Blood pool and flow were studied in transplanted adenocarcinomas on the legs of mice. The animals' red blood cells were labelled in vivo by consecutive injections of a stannous compound and 99mTc-pertechnetate. The distribution of radioactivity was then recorded continuously with a gamma camera. This method allows prolonged and repeated estimations of blood supply to undisturbed tumours in conscious mice.It was found that in small tumours (under 1 ml) circulating blood pool was usually high, often 2 or 3 times that in normal leg tissues. In tumours bigger than 1 ml blood pool per unit volume tended to be lower but was still about 1.5 times the normal tissue level. This relatively large blood volume would seem to be outweighed by a very slow rate of flow. Even in the small tumours blood perfusion was greatly reduced compared to that in the normal leg. The blood pool results here provide no evidence that in tumours larger than 1 ml blood supply decreased progressively with growth.
SUMMARY To provide an objective rapid means of excluding extrahepatic biliary atresia (atresia), a hepatic index was devised from the ratio of the net hepatic to cardiac distribution of 99mTc diisopropyl iminodiacetic acid or methylbrom iminodiacetic acid between 2-5 and 10 minutes after injection. The hepatic index was compared with subjective assessment of abdominal scintigraphy performed repeatedly over 24 hours. In 22 infants with hepatitis the hepatic index ranged from 5*03 to 14-9, one having no excretion on scintiscan. In 26 infants with atresia the index ranged from 0-49 to 4-26 and in two with paucity of intralobular bile ducts it was 1-85 and 3-69. None of these infants had excretion apparent on scintiscans. Similarly, low hepatic indices occurred in four infants with liver dysfunction but pigmented stools, three of whom had no excretion apparent on scintiscans. These preliminary studies suggest that a hepatic index of greater than 5 is much more rapid and as specific in excluding atresia as repeated abdominal scintigraphy.
99Tcm-pyridoxylidene glutamate (99Tcm-PG) scans have been carried out in 24 jaundiced adults (mean total bilirubin 255 mumol/l and 11 infants with prolonged obstructive jaundice (mean total bilirubin 165 mumol/l). Absence of radioactivity in the gut was interpreted as complete biliary obstruction which was the cause of jaundice in ten adults and six infants. Using this criterion occlusion or patency of the bile ducts was correctly determined in 21 adults and eight infants. False-negative gut images were found in one adult and two infants, and three scans were inconclusive (two adults, one infant). The scan was unable to show details of the site of obstruction or pathology but the technique was simple and atraumatic and was safely performed in patients with serious complications, e.g. renal failure, coagulation defects, septicaemia. In infants the 99Tcm-PG scan compared well with the 131I rose bengal faecal excretion test and with liver biopsy in the investigation of prolonged obstructive jaundice. Repeat scans in infants with biliary atresia were used to assess postoperative bile drainage. It is suggested that 99Tcm-PG scanning is useful screening test in difficult cases of jaundice. It is especially useful in frail patients, and patients with complications.
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